Provided is a highly safe battery device in which the accuracy of an overcurrent detection current value is high. A charge and discharge control circuit includes an overcurrent detecting terminal, an overcurrent detecting circuit for detecting overcurrent of a secondary battery, the overcurrent detecting circuit being connected to the overcurrent detecting terminal, and a constant current circuit for causing a current to flow to the overcurrent detecting terminal.
Legal claims defining the scope of protection. Each claim is shown in both the original legal language and a plain English translation.
1. A charge and discharge control circuit for detecting a voltage and abnormality of a secondary battery, the charge and discharge control circuit comprising: an overcurrent detecting terminal; an overcurrent detecting circuit for detecting overcurrent of the secondary battery, the overcurrent detecting circuit being connected to the overcurrent detecting terminal; a resistor connected to the overcurrent detecting terminal; a constant current circuit for causing a current to flow to the overcurrent detecting terminal and the resistor; wherein the overcurrent detecting circuit compares a reference voltage with a voltage of the overcurrent detecting terminal including a voltage generated by the current flowing through the resistor; and wherein the resistance value of the resistor is adjusted to set an overcurrent detection current value at a predetermined setting value and a threshold voltage for the overcurrent detecting circuit to output a detection signal is a voltage having the value of the voltage generated by the current flowing through the resistor subtracted from the reference voltage.
A circuit protects a secondary battery from overcurrent and monitors its voltage. It uses a dedicated terminal for overcurrent detection, linking to an overcurrent detection circuit. A resistor is connected to this terminal. A constant current source drives current through both the terminal and resistor. The overcurrent detection circuit compares the terminal voltage (which includes the voltage drop across the resistor) against a fixed reference voltage. The resistor's value is chosen to set the desired overcurrent trip point. The detection circuit triggers when the terminal voltage, influenced by the current through the resistor, drops a certain amount below the reference voltage, signaling an overcurrent condition.
2. A charge and discharge control circuit according to claim 1 , wherein the overcurrent detecting circuit comprises: a reference voltage circuit; and a comparator circuit for comparing a voltage of the overcurrent detecting terminal with a voltage of the reference voltage circuit.
The overcurrent protection circuit for a secondary battery refines the detection process. The overcurrent detection circuit includes a stable reference voltage generator and a comparator circuit. This comparator continuously compares the voltage at the overcurrent detection terminal (influenced by the current through a resistor and constant current source) with the precisely defined reference voltage. When the terminal voltage dips below a specific threshold relative to the reference voltage, indicating an overcurrent situation in the battery, the comparator triggers, signaling the need for protective action. This allows fine tuning of the overcurrent threshold for the battery.
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February 25, 2014
May 9, 2017
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